Connecter for electrical conduits



Oct. 4, 1938. J. M. G. FULLMAN Re. 20,873

CONNECTER FOR ELECTRICAL; CONDUITS Original Filed July 26, 1928 WITNESSReissued Oct. 4, 1938 UNITED STATES Re. 20,873 I CONNECTER FORELECTRICAL OONDUITS James M. G. ,Fullman,

Sewickley, Pa., assignor,

by mesne assignments, to National Electric Products Corporation, acorporation of Delaware Original No. 1,769,947, dated July 8, 1930,Serial No. 295,550, July 26, 1928. Application for reissue July 20,1938,

3 Claims.

In connecting electrical conduits and armored cables to outlet boxes andother electrical fittings it is usual to cut away the conduit wall orthe sheath of the cable and to pass the unsheathed conductors into thebox for making the desired.

been proposed recently to provide a bushing of insulating material whichcan be slipped over the exposed conductors where the armor is cut away,or slipped between the conductors and the armor of a cable, and having ashoulder bearing against the sharp metallic edge of the armor, as shownand described in Letters Patent No. 1,687,013, dated October 9th, 1928.When such a bushing is used at the joint between an armored cable and anoutlet box with connecters of the present usual types, it is largely oraltogether hidden within the connecter because the end of the connecteroverhangs the bushing, so that its presence is not apparent to aninspector or other observer.

The present invention provides an improved connecter binding the cableto the outlet box, and having means for holding the insulating andprotective bushing in place, which will permit the bushing to bevisible, and thus permit ready inspection of the system.

An object of the invention is to construct a new and novel combinationof armored cable or conduit, a thin walled bushing, a connecter havinginwardly projecting means which bears upon and .10 overhangs thebushing, and said connecter having inspection openings so that thebushing is visible through an inspection opening when the combination isassembled within a box hole.

In the accompanying drawing Figure 1 is a sec- 45 tional elevation of anoutlet box-wall with the combination of an armored cable provided withan insulating bushing in its throat and joined to an outlet box by myimproved connecter.

Figure 2 is a front elevation of the structure 50 shown in Figure 1.

Figure 3 is a view of the bushing in elevation.

Figure 4 is a front view of the bushing.

Figure 5 is a view of the box wall in section and with the cable andconnecter, in elevation, secured in the box hole as shown in Figure 1.

Serial No. 220,397

(Cfl. 247--25) The wall of the outlet box is designated by the numeralI, and the usual outlet opening by the numeral 2. The flexible armoredcable 3 herein shown is of the well known type. The conductors 4 havewound upon them a jacket 5 of helically 5 coiled strips of fibrousmaterial, such as paper, and the metallic armor E is coiled tightlyaround the jacketed conductors. When the edge of the armor 6 has beencut away, the jacket 5 is unwound for a suitable distance and brokenoil, thus leaving an annular space around the conductors within thearmored cable back of the cutaway edge. Into this space there is slippedaround the conductors the split tubular bushing 1 formed of thininsulating material and having at its outer edge the integral shoulder 8which bears against the cut-away edge of the armor, leaving the exposedconductors 4 projecting therefrom.

The connecter may be of a variety of suitable forms, but for purposes ofillustration I have shown herein the usual pinch connecter having aforward cylindrical threaded portion 9 projecting through the opening inthe outlet box, with the shoulder l0 bearing against the outer face ofthe wall of the box, the transverse slit II, and the rearwardlyprojecting bifurcated barrel portion I2 having the opposite ears l3connected by the binding screw [4, by means of which the bifurcatedbarrel portion is caused to pinch the armored cable tightly. Thebifurcated barrel portion l2, ears I3, and binding screw I4 areillustrative of any means for securing a cable or conduit within thebarrel portion of the connecter. The connecter is held in place in theopening by means of the lock nut I5 screwed upon the threaded innerportion 9 and bearing against the inner face of the wall of the box. Thescrew threads, shoulder at the end of the screw threaded portion 9, andthe lock nut I5 are illustrative of any suitable means for securing theconnecter within a box hole.

In order to retain the bushing in place in such a way that it will bevisible to an observer, the connecter is provided at the inner edge ofthe portion 9 with a plurality of inwardly projecting fingerswhich'overhang and bear upon the outer face of the shoulder 8 of thebushing, preventing its displacement, while at the same time the bushingbetween the fingers is readily visible to an inspector or other observerthrough the inspection openings between the fingers. The inspectionopening may be of any suitable form so long as it renders the bushingvisible for ocular inspection when the cable and connecter areassembled, such as in a box hole. In fact, as shown in Figures 1 and 5,the shoulder of the bushing projects slightly beyond the side edge ofthe lock nut I5, so that it can be seen from the side as well as fromthe front. This is of considerable practical advantage in the installation and inspection of electrical conduit systems of this type.

It will be understood that the specific form of the connecter may bevaried, and it will also be understood that while the invention is ofparticular advantage in the use of flexible metallic armored cables, itmay be used to advantage in the installation of electrical conduits o1other forms. Since the metallic armor for flexible armored cables is inevery sense a conduit for conductors, irrespective of the fact that theconductors and the armor are normally a unitary structure, the termconduit will be understood to apply both to the armor of flexiblearmored cable and to conduit not initially having conductors therein,but through which insulated conductors are adapted to be pulled afterinstallation of the conduit system.

What is claimed is:

1. The combination with an armored cable, of a bushing of insulatingmaterial having a tubular barrel portion contained Within the cablearmor and a shoulder bearing against the end of the armor, and aconnecter and means for securing it to the cable, said connecter havinga portion projecting beyond the end of the cable armor and havinginwardly projecting fingers adapted to bear upon the bushing shoulderand retain the bushing in place.

2. The combination with a conduit having insulated conductors therein,of a bushing of thin insulating material having a tubular barrel portioncontained between the conduit and the conductors to shield the conductorinsulation from the sharp edges of the conduit, and a shoulder bearingagainst the end of the conduit, and a connecter and means for securingit to the conduit, said connecter having a portion projecting beyond theend of the conduit and having inwardly projecting means adapted tooverhang and bear upon the bushing shoulder and retain the bushing inplace, and said connecter having at least one inspection opening throughthe projecting portion of the connecter whichrenders the bushing visiblewhen the combination is assembled in a box hole.

3. In an assembly of an outlet box, cabinet, panel or the like having anoutlet hole in the wall thereof and a conduit having insulatedconductors therein, a bushing of thin insulating material having atubular barrel portion contained between the conduit and the conductorsto shield the conductor insulation from the sharp edges of the conduit,and a shoulder bearing against the end of the conduit, in combinationwith a connecter having means for securing it in an outlet hole andmeans for securing it to the conduit, said connecter also having aportion projecting beyond the end of the conduit and having inwardlyprojecting means adapted to overhang and bear upon the bushing shoulderand retain the bushing in place, and said connecter having at least oneinspection opening through the projecting portion of the connecter whichrenders the bushing visible when the combination is assembled in anoutlet hole.

JAMES M. G. FU'LLMAN.

